The present invention relates to electromagnetically operated valve units, and more particularly to an improvement of an electromagnetically operated valve unit which includes a main body of non-magnetic material having a closed end and an open end, a cover member of non-magnetic material sealingly fitted to the open end of the main body through a lateral plate member of magnetic material, a solenoid coil wound around a bobbin and contained within the main body, a stationary core of magnetic material concentrically fixed within the bobbin, a moving-core axially movable within an axial bore extending coaxially with the stationary core through the lateral plate member, resilient means for biasing the moving-core in one direction, a valve assembly cooperating with the moving-core, a U-shaped yoke member having a head portion engaged with an extension of the stationary core extending from the closed end of the main body and a pair of longitudinal arms extending from the head portion along both sides of the main body, and a bracket coupled over the cover member and secured to the respective arms of the yoke member.
In such a conventional valve unit as described above, a magnetic path of the solenoid coil is formed across the respective cores, the yoke member and the lateral plate member to generate a linear attraction force acting on the moving-core upon energization of the solenoid coil. With an assembly of the valve unit, as shown in FIG. 5, a lateral plate member 16' merely engages at its opposite ends with a pair of longitudinal arms 21'b of a U-shaped yoke member 21'. When the arms 21'b of yoke member 21' are fastened by caulking 21'c to a bracket 22' in process of assembly of the valve unit, the respective arms 21'b are irregularly deflected in the outward direction. This causes undesired displacement of the respective arms 21'b of yoke member 21' relative to the lateral plate member 16' and results in decrease of the engagement area between the lateral plate member 16' and the yoke member 21'. As a result, the magnetic path of the solenoid coil decreases at the engaged portions of the lateral plate member 16' with the respective arms 21'b and changes in each product of the valve unit.